US Patent 9184054 Method for integrated circuit patterning

Provided is a method of patterning a substrate. The method includes forming a resist layer over the substrate, wherein a layer of resist scum forms in between a first portion of the resist layer and the substrate. The method further includes patterning the resist layer to form a plurality of trenches in the first portion, wherein the layer of resist scum provides a floor for the plurality of trenches. The method further includes forming a first material layer in the plurality of trenches, wherein the first material layer has a higher etch resistance than the resist layer and the layer of resist scum. The method further includes etching the first material layer, the resist layer, and the layer of resist scum, thereby forming a patterned first material layer over a patterned layer of resist scum over the substrate.